Collect 30 cc's of blood in clot tubes from Breast Cancer Demonstration Project screenees. Prepare the serum fraction from each blood sample and rapid freeze such sera. Store serum samples prior to shipment, record any temperature deviations during storage. Periodically ship the appropriate serum samples to NCI designated bank facility under conditions designated to prevent sample thawing. Maintain accurate records for sample acquisition, coding, and processing. Provide definitive diagnosis of the pathology of the breast lesion(s) and the status of each patient. Allow access to specimen slides and blocks for review of pathologic findings. Prepare and forward the clinical information form for each patient whose serum has been sent to the bank facility. Establish evaluation mechanisms and standards, and assure all program objectives are achieved. Collect one 30 ml postoperative specimen from post-biopsy cases within the first month and process in the same manner.